Pains in early pregnancy

I'm soooo worried, I'm 4 and a half weeks pregnant so very early. Been feeling great, very tired, bloated, windy, sore boobs etc. but good. I was originally due my period today and last night I got bad period pains. The kind I normally get just before I come on. It's lasted until now including some sharp twinges and some small twinges right down below. I haven't bled and read on the Internet this is quite normal unless you start bleeding, but I am so worried that something isn't right?? Any advice would be gratefully received!

I've had terrible terrible tummy cramps. I think this is normal and caused be uterus growth but if you are worried call your doctor. It is very scary but I'm sure it's a common symptom for some women x